The present invention relates to the continuous casting of metal, particularly steel in the horizontal mode whereby particularly molten metal is fed into a horizontally oriented mold for continuous casting and being cooled and wherein a casting or ingot is extracted from the mold under consideration of particular conditions such as extraction speed, extraction length, retraction speed, retraction length and holding periods in between the alternatingly occuring extraction and retraction steps of the casting.
Horizontal casting of metal on a continuous basis offers certain problems. In most instances certain production stroke marker cracks or grooves are observed which in certain cases particularly for some high quality steel grades render the process useless. In case the expert applies particular careful handling to these grades of steel the throughput for the casting process reduces.
It is known (see for example Berg- und Huettenmannische Monatshefte 1983, Volume 3, Pages 65-71) to attempt to optimize the various parameters involved in the casting process. It has also been considered to avoid the drawback of marker formation on account of the extraction process by increasing the frequency of extraction from 100 per minute, as practiced presently, to 200 or 300 cycles/minute in order to avoid skin rupture cracks on account of stroke markers or the like. These high frequencies, however, are difficult to obtain by means of a conventional extraction machines using roller drives; and the problem is increased if the cross section of the casting is larger and the overall casting weight/length is very high.
In the case of roller drives the force is applied to the casting in practically pointlike fashion which in the case of high speeds, large cross section and high weights means considerable expenditure of force which in turn can readily deform the casting in view of the fact that at the zone of engagement the skin is still very thin. It has been tempting to use a multiroller drive for this purpose but the problem here is the lack of adequate synchronism.
From the point of view of apparatus and equipment certain hydraulically operated extraction machines are known, e.g. through the German printed patent No. 32 06 501 corresponding to U.S. patent application Ser. No. 455,465 filed on Jan. 03, 1983. The casting is gripped by means of brackets or the like and without play move the casting rather exactly. Such an extraction machine does indeed permit trouble-free optimization of the casting method.
The various parameters which were relevant for horizontal casting of metal have been mentioned above. These parameters are used to determine the casting speeds, the rate of intermittency of extraction etc. These parameters are used to calculate casting speed and cycle time of extraction. Moreover, the additional factors such as the material of the mold, its shape, the cooling condition have to be considered. The casting material itself i.e. the metal is an important parameter; also electromagnetic stirring of the liquidous core is to be considered.